fix(security): harden GitHub Actions workflows against expression injection

Move ${{ }} expressions from run: blocks into step-level env: blocks,
then reference them as properly-quoted shell variables.

Signed-off-by: Marco Nenciarini <marco.nenciarini@enterprisedb.com>

go.mod

@@ -5,7 +5,7 @@ go 1.25.0
 toolchain go1.25.6
 
 require (
-	github.com/cert-manager/cert-manager v1.19.3
+	github.com/cert-manager/cert-manager v1.19.2
 	github.com/cloudnative-pg/api v1.28.0
 	github.com/cloudnative-pg/barman-cloud v0.4.1-0.20260108104508-ced266c145f5
 	github.com/cloudnative-pg/cloudnative-pg v1.28.0

go.sum

@@ -12,8 +12,8 @@ github.com/blang/semver/v4 v4.0.0 h1:1PFHFE6yCCTv8C1TeyNNarDzntLi7wMI5i/pzqYIsAM
 github.com/blang/semver/v4 v4.0.0/go.mod h1:IbckMUScFkM3pff0VJDNKRiT6TG/YpiHIM2yvyW5YoQ=
 github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=
 github.com/cenkalti/backoff/v5 v5.0.3/go.mod h1:rkhZdG3JZukswDf7f0cwqPNk4K0sa+F97BxZthm/crw=
-github.com/cert-manager/cert-manager v1.19.3 h1:3d0Nk/HO3BOmAdBJNaBh+6YgaO3Ciey3xCpOjiX5Obs=
-github.com/cert-manager/cert-manager v1.19.3/go.mod h1:e9NzLtOKxTw7y99qLyWGmPo6mrC1Nh0EKKcMkRfK+GE=
+github.com/cert-manager/cert-manager v1.19.2 h1:jSprN1h5pgNDSl7HClAmIzXuTxic/5FXJ32kbQHqjlM=
+github.com/cert-manager/cert-manager v1.19.2/go.mod h1:e9NzLtOKxTw7y99qLyWGmPo6mrC1Nh0EKKcMkRfK+GE=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cloudnative-pg/api v1.28.0 h1:xElzHliO0eKkVQafkfMhDJo0aIRCmB1ItEt+SGh6B58=